biological membranes

Question 1

which direction do the molecules spread in diffusion?

Answer 1

from areas of higher concentration to lower concentration

Question 2

what 3 things affect the rate of diffusion?

Answer 2

surface area, difference in concentration,

Question 3

what are lysed, normal and crenation in blood cells?

Answer 3

lysed- the net movement into the cell is more dilute & the cell wall bursts if concentration of blood is too dilute, normal- same concentration in and out of cell, crenation- inside has more water than outside of cell so H2O moves out

Question 4

what happens in a plant cell, why doesn’t it burst?

Answer 4

the plant cells swell, but cant burst due to the cell wall, the vacuole just gets very large

Question 5

what is endocytosis?

Answer 5

bulk transport into the cell, the membrane folds into a pouch surrounding the cell forming a vesicle

Question 6

what is exocytosis?

Answer 6

cell waste or cell products, moves towards the cell membrane and fuses to release cotents by exocytosis

Question 7

in active transport which direction do the molecules move?

Answer 7

low to high and this requires ATP

Question 8

what does facilitated diffusion use?

Answer 8

channel and carrier proteins

Question 9

does active transport move substances towards or against the concentration gradient

Answer 9

against

Question 10

how do cells take in substances

Answer 10

endocytosis

Question 11

how do cells secrete

Answer 11

exocytosis

Question 12

what is needed for endocytosis and exocytosis

Answer 12

ATP

Question 13

what is osmosis?

Answer 13

diffusion of water molecules

Question 14

state in order the stages of mitosis

Answer 14

(interphase), prophase,

Metaphase anaphase, telophase, (cytokinesis)

Question 15

what does meiosis produce

Answer 15

gametes for sexual reproduction

Question 16

where do the chromatids cross over

Answer 16

prophase 1

Question 17

how does meiosis produce genetically different cells?

Answer 17

crossing over of chromatids- different alleles and independent assortment of chromosomes- when the homologous pairs line up its random so the 4 daughter cells have different combinations of the parental chromosomes

Question 18

what are stem cells?

Answer 18

unspecialised cells

Question 19

what do cells in bone marrow differentiate into

Answer 19

neutrophils and erythrocytes (red and white blood cells)

Question 20

how might stem cells be used to treat Parkinson’s?

Answer 20

transplanted stem cells are hoped to reproduce the dopamine producing receptors

Question 21

how are neutrophils and erythrocytes specialised?

Answer 21

neutrophils- flexible shape allows them to engulf, many lysosomes in cytoplasm containing digestive enzymes to break down invading particles, erythrocytes- biconcave shape for larger SA for gas exchange, no nucleus so more room for haemoglobin

Question 22

how are epithelial cells and sperm cells specialised

Answer 22

epithelial cells - have cilia that beat to move particles away, squamous epithelium are very thin in the lungs for gas exchange, sperm cells- have flagellum so they can swim to the egg, the head had digestive enzymes to penetrate the egg

Question 23

what is meant by tissue

Answer 23

a group of cells that are specialised to work together to carry put a particular function

Question 24

what are the 4 types of animal tissue?

Answer 24

squamous epithelium, ciliated epithelium, muscle tissue, cartilage

Question 25

what are the 2 types of plant tissue

Answer 25

xylem and phloem

Question 26

what is an organ

Answer 26

a group of different tissues that work together to perform a particular function

Question 27

give an organ found in a plant and one found in an animal

Answer 27

lungs and leaves

Question 28

what makes up and organ system, give an example

Answer 28

different organs, the respiratory system